<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <p>姓名：<input type="text" v-model="name"></p>
        <p>年龄：<input type="text" v-model="age" :disabled="isDisabled"></p>
    </div>
    <script src="../vue.js"></script>
    <script>
        new Vue({
            el:'#app',
            data () {
                return {
                    name:'',
                    age:'',
                    isDisabled:true,
                }
            },
            watch: {
                name:function(newName,oldName){
                    if(newName){
                        setTimeout(()=>{
                            this.age=21;
                            this.isDisabled=false;
                        },2000)
                    }
                    else{
                        setTimeout(()=>{
                            this.age='';
                            this.isDisabled=true;
                        },2000)
                    }
                }
            }
        })
    </script>
</body>
</html>